Apparatus for continuously tipping and flagging bristles



INVENTOR ATTORNEY I Nov. 10, 1959 F. E. ANDERSON APPARATUS FORCONTINUOUSLY TIPPING AND FLAGGING BRISTLES 2 Sheets-Sheet 1 Filed Oct.22. 1958 Nov. 10, 1959 F. E. ANDERSON APPARATUS FOR CONTINUOUSLY TIPPINGAND FLAGGING BRISTLES- Filed Oct. 22. 1958 2 Sheets-Sheet 2 z a F/ATTORNEY "cries of the abrasive elements.

United States Patent Q APPARATUS FOR CONTINUOUSLY TIPPING AND FLAGGINGBRISTLES Frederick Edwin Anderson, Parkersburg, W. Va, assignorto E. I.du Pont de Nernours and Company, Wilmington, Del., a corporation ofDelaware Application October 22, 1958, SerialNo. 768,985 9 Claims. c1;51- 80 This invention'relates to an apparatus for tipping and rflaggingfilaments of synthetic materials.

to further manufacturing operations to produce tips which simulatethose-of animal bristles. The process of tapering the end of the bristleto a fine point is known in the industry as tipping, while the processof splitting the tips of the bristles to form" a plurality ofhairlikepoints .at theend of a bristle is known as flagging.

A'complicating factor in the operations of tipping and flaggingsynthetic filaments is the diffieulty of handling loose filaments whileattempting to perform operations on each filament. In the prior art,synthetic or natural bristles have been handled as a cylindrical bundleof loose bristles held in the form of a bundle by an encircling rubberband. In my earlier patent, US. 2,804,-

972, issued SeptemberB, 1957, there is described and claimed a novelmethod of packaging filaments by sewing a thin bed of filaments to a webof paper or other material to form a continuous belt of filaments. Thisnovel package can be usefully adapted to the present process of tippingand flagging.

'It is an object of this invention to provide an apparatus capable ofreceiving a thin bed of filaments, which may or may not be sewn toa'tape in the form of a belt,

and continuously tipping and flagging those filaments for subsequent useas brush bristles. apparent from the detailed description and attacheddrawings explaining and illustrating this invention;

The above objects are accomplished by providing an apparatus comprisingtwo rotatably mounted shafts supplied with means for rotatingthese'shafts at high speeds and in opposite directions; a multiplicityof thin abrasive elements mounted on each shaft, the abrasive elementsbeing in the form of solid abrasive wheels, brushes made of abrasivebristles, or other abrasive assemblies ofsimilar configuration; aconveyor adapted to move a thin bed of filaments along a path parallelto, and in a plane substantially midway between, the axes of saidshafts; means for clamping the bed of filaments to the moving conveyor,which, in turn, is positioned adjacent to periph- By means of thisapparatus a bed of filaments, whether or not sewn to a tape to form abelt, is fed into the conveyor which clamps the midportion of the bedtightly to the conveyor while the flexible tips of the filaments arecarried past two coacting, counter-rotating, high speedabrasiveassemblies which taper-grind the ends of the filaments and flag thetapered tips. The abrasive elements may be in the form Other objectswill be.

. Patented, Nov. 10, -1959 of solid abrasivewheels or discs, flexibleabrasive bristles,

substantially inflexible abrasive rods,'or other-such-elements thatmaybe apparent tothose skilled:in thisv art.

The filaments being tipped may "be syntheticpolymer filaments, e.g.nylon,whether tapered or level, or they may be natural filaments,e.g...horsehair 'or .animal bristles; and furthermore, the filaments tobe'itipped may be loose,-'sewn to atape as describedabove; mountedwheels.

" in the ferrule of a'paintbrushror.in.anyother-conceivable arrangementwhereby. .thextips 'of the. filaments may be inserted into. theabrasive. elements of this apparatus to be tipped and flagged.

Tapered, synthetic filaments maybe prepared by'form- .ing .a continuousfilament. having .regula'rly :zrepeating segments in which the diameterof the filamentchanges from a minimum to amaximum and back to a:minicontinuous filament. at .each :point of minimumLdiam- 'eter,filamentsegments are formed. By cuttingone of these segments at itsmidpointpwherethe:maximumrdrameter occurs, two individualatapered,synthetic bristles are formed. It may be seen that,:,as an alternative:ar-

'rangement of this apparatus; twopairs of abrasive wheels maybe-positioned so asto :face each other, and may tip and flag, at thesame time, each end of the filament segments in a-bed travelling pastthe abrasive wheels, after which those segments may be cut in halfhtoform. two beds of individual bristles. "It is, of course, to beunderstood that this apparatus may be employed .totip and flag levelfilaments as well as tapered filaments. -:In' the attached drawings,Figure l-is a front elevation of one embodiment of the apparatus;Figure2 isacross-sectional view taken at A-A on Figure 1; Figure 3 isatop plan viewof-the apparatus .shown in Figure 1;- Figure 4 is aviewsimilar to that of Figure 2 except that the abrasive Wheels aresubstituted by brushes made of abrasive bristles; and Figure 5 is anisometric view of a sparsely populated brush which'may be used in placeof the brushes shown in Figure 4.

Specifically referring to Figure 1, it may be seenthat the apparatuscomprises two shafts, 1 and Zydrivenat high speed by a means which isnot'shown so as to rotate in opposite directions with respect to eachother. One suitable driving method would be to attach a motor'to shaft2, turning the shaft in the direction indicated at=l-3, and transmittingthe opposite rotation to shaft 1 th-ru spur gears 4. A series of thinabrasive wheels 5 are mounted on each shaft with a spacing betweenadjacent One suitable alternative for an abrasive 'wheel is a thin wheelbrush with abrasive bristles or abrasive ma.- terials cemented to thebristles of the brush. The proper spacing may be supplied by the use ofspacers 6. "Wheels 5 are afiixed to shafts 1 or2 and rotate with saidshafts. The spacing between adjacent wheels 5 on a shaft is greater thanthe'thickne ss of a wheel so as to permit the wheels mounted on oneshaft to extend into the spaces between wheels on the other shaft (showngenerally at 7). The'mounting and spacing of wheels 5 are such thatthere is no contact between wheels. The spacing may be regular, asshownin Figure 1, or irregular. Any number of abrasive wheels 5 may be placedin series along shafts 1 and 2, limited only by the size of theapparatus. Another suitable alternative is to provide a cylindricalbrush for each of the two shafts, 1.and'2, rather than a series of thin,wheel'brushes; and,.in the case of this alternative arrangement, theouter peripheries'of the two brushe-s'normally are substantiallytangentas shown in Fig. 4, rather than the overlapping arrangement of Fig. 2,although as described below some overlapping may beem ployed when usingbrushes as the abrasive assembly. Shafts 1 and 2 are, of course, mountedin suitable bearings shown schematically at 8 and 9.

By cutting the The foregoing part of the apparatus of Figure 1 comprisesthe grinding and flagging mechanism. The remainder of the apparatus isthe conveyor system which moves the bristles or filaments, in the formof a continuous or intermittent bed, past abrasive wheels 5 in order topermit those bristles or filaments to be tipped and flagged. Acontinuous bed of filaments may be seen entering the apparatus from theright in Figures 1 and 3. This bed of filaments comprises, in itspreferable form, a thin (not more than about inch thick) layer offilaments, oriented and aligned with each other in a direction which isgenerally perpendicular to the long axis of the bed and to the directionof travel through the apparatus for tipping and flagging. In theembodiment shown in Figures 1 and 3 the bed of filaments is attached toa paper tape by some form of stitching, e.g. by two rows ofsingle-thread chain stitching. Such an article of filaments sewn to atape is referred to herein as a belt, and it can be subjected to ratherrough handling without disturbing the relationship of the filaments tothe paper tape. It, of course, is not necessary to the operation of thisapparatus that the tape be present since it merely affords a convenientway of handling the filaments entering and leaving this apparatus. Belt10 is fed into a moving conveyor, such as that formed by the combinationof chains 11 and chains 12. Other types of continuous or intermittentconveyors are useful in certain embodiments of this invention. Chains 11and 12, in their movement from right to left, pass between clampingangles 13 and 14, which causes chains 11 and 12 to clamp belt 10 tightlybetween the chains as the filaments of belt 10 are passed into contactwith wheels 5. Chains 11 and 12 are mounted on sprockets 15, which aredriven in the directions indicated by arrows 16, such that the chainsmove in the same direction and at the same speed. Belt 10 leaves theapparatus at the left side of Figure l with one end of each filamenthaving been subjected to the tipping and flagging action of wheels 5.Belt conveyors, or other known alternatives, may be used in place ofchains 11 and 12.

The cross-sectional view shown in Figure 2 illustrates the positioningof the filaments and the abrasive wheels. The direction of rotation ofwheels 5 is shown by arrows 17. Belt 10 is clamped tightly in place bychains 11 and 12, leaving the tips 18 of the filaments to be contactedby wheels 5 rotating at high speed. Clamping angles 13 and 14,preferably covered with a rubber-like strip 19, provide the forcenecessary to clamp belt 10 firmly to the moving chains 11 and 12.Support 20 provides a base onto which clamping angles 13 and 14 andsprocket shafts 21 and 22 may be attached. Driving means for rotatingshafts 21 and 22 in the indicated directions are not shown. There doesnot appear to be any critical limit to the amount of overlapping ofwheels 5 as viewed in Figure 2. The geometry and space requirements ofchains 11 and 12, strips 19, and clamping angles 13 and 14 willdetermine the amount of overlap to be tolerated. As shafts 1 and 2 aremoved apart, the distance between the top of angle 13 and the bottom ofangle 14 must be made less and less in order that tips 18 may be placedin contact with wheels 5. Generally, about /2 to inch of the tip of thefilaments in belt 10 should be placed in contact with wheels 5. If agreater amount of the filament tip is placed in contact with the wheels,the filament receives an excessive amount of grinding at some pointabove the tip. On the other hand, if a lesser amount of the filament tipis placed in contact with the wheels, the filament tip is ground to arather blunt point.

All of wheels 5 may be replaced, in one embodiment of this inventionwith a cylindrical brush 25 on each of shafts 1 and 2, as shown inFigure 4. In such a case there is no overlapping as shown in Figure 2,but instead, the peripheries of the two brushes 25 just barely tong! orare separated by a very small clearance. The best filaments 18 which arebeing ground thereby may extend into the interior of the abrasivebrushes.

In one particularly desirable embodiment there is employed a cylindricalbrush which is sparsely populated with bristles as shown in Figure 5.The bristles are posit'ioned radially and spaced at equal angles fromeach other around the brush core, adjacent bristles being spaced apartfrom about 2 to about 45 as shown at 28. In the axial direction,adjacent bristles may be spaced any convenient distance, 29, dependingupon the total length of the cylindrical brush. The bristles arepreferably arranged in rows parallel to, and perpendicular to, the axisof the brush, thus forming a rectangular pattern, the distance betweenadjacent perpendicular rows normally being about the same as thedistance between adjacent parallel rows. As an illustrative example, thebrush core may be 2-3 inches in diameter with bristles extending 1-2inches outward from the surface of the brush core. The spacing betweenadjacent bristles in a circumferential direction may be approximately 10(measured at the center of the brush) while the axial spacing may befrom about A; inch to 6 inch for brushes which are of a convenientlength of about /2 to 2 feet. The brush bristles are generally rod-likein shape and may be wires; synthetic polymer filaments, e.g. nylon;natural animal hairs or bristles; reeds; rods; or the like. The abrasivecharacter of the brush bristles may be achieved by coating a bristlewith an adhesive and applying abrasive particles to the coating. Thedistance between the shafts on which these brushes are mounted issubstantially the same as the outside diameter of the brushes, althougha small amount'of overlapping, e.g. up to about inch, may be usefullyemployed by indexing the two coacting brushes so that, like the meshingof gears, the bristles of one brush mesh with the space between bristlesof the other brush at the plane midway between the two shafts 1 and 2.

Figure 3 indicates the general arrangement of belt 10, wheels 5, andchains 11 and 12. Belt 10, moving in the direction of arrow 23, is movedby chains 11 and 12, clamped tightly by angles 13 and subjected to theopposed, intermeshing coaction of wheels 5. The tips 18 of the filamentsare free to bend and flex, and are, therefore, subject to the abrasiveaction and the impact of each of wheels 5 as the conveyor chains carrybelt 10 from right to left. The clearance 24 between adjacentintermeshing wheels should be as small as possible in order to conservespace, but clearance 24 should not be as small as the diameter of asingle filament. Normally, if clearance 24 is about A; inch, bothpurposes will be adequately served. Wheels 5 are preferably made of afine grade of abrasive material, such as carborundum. The abrasiveparticles are somewhat loosely bonded so that, as abrasive particles aretorn loose, new, sharp particles. are exposed for further grinding.

As an illustration of the effectiveness of the apparatus of thisinvention, a belt of tapered nylon filaments approximately 6 inches longtapering from an average diameter of about 0.012 inch at the large endto about 0.008 inch at the small end was passed through an apparatussuch as that shown on the attached drawings. The abrasive wheels were/1, inch thick by 7 inches in diameter. The spacing between wheels onthe same shaft was about /2 inch, which, therefore, provided a clearanceof about A: inch between adjacent intermeshed wheels, one from eachshaft. The wheels were driven at'a speed of 3470 rpm. The belt offilamentswas driven at a linear spced of 15 inches per minute. After thefilaments were subjected to approximately 5 minutes of such treatment,the tips of the filaments were examined by a microphotograph, whichrevealed that the taper differed from filament to filament, some beingfinished to a hair-like tip while other tips were not quite so finelyground. All filaments, however, exhibited the effects of being reducedin diameter by the taper-grinding, and substantially all of thefilaments were split or flagged at the tip for a length of aboutone-sixteenth of an inch or less.

Even better results have been obtained using a pair of sparselypopulated brushes as shown in Figure 5, as the abrasive elements fortipping and flagging tapered nylon filaments. The bristles of thebrushes in one instance were nylon filaments, 1% inches long and 0.040inch in diameter, coated with an epoxy adhesive and carborundumparticles. In another instance wires, some what smaller in diameter thanthe nylon bristlw mentioned above, were employed with the same type ofabrasive coating.

Many variations may be introducedinto the apparatus of this inventionwithout departing from the spirit thereof, and this inventioon is notintended to be limited other than by the terms of the appended claims.

I claim:

1. An apparatus for taper-grinding and flagging of filaments forsubsequent use as brush bristles, which comprises two rotatably mountedshafts; means for rotating said shafts at high speeds in directionsopposite to each other; each of said shafts having mounted thereon amultiplicity of thin abrasive elements such that all of the saidelements on one shaft combine to form an abrasive assembly which issubstantially cylindrical in shape; a conveyor adapted to move a thinbed of filaments along a path which is parallel to, and lies in a planesubstantially midway between, said shafts; means for tightly clampingsaid filaments against movement with respect to said conveyor whileleaving the filament tips which are to be ground free to flex and tobend, the individual filaments being aligned substantially perpendicularto the path of said conveyor; the distance between said shafts, thediameter of said abrasive assembly and the positioning of said conveyorbeing such that said filament tips are brought into contact with atleast one of said abrasive assemblies throughout the movement of saidbed along the entire length of said abrasive assembly.

2. The apparatus of claim 1 in which said abrasive assembly comprises aseries of spaced, disc-like units having a diameter greater than thedistance between said shafts; the units on one shaft extending into thespaces between, but not in contact with, the units on the other shaft.

3. The apparatus of claim 1 in which said abrasive elements are rod-likeunits extending radially from a cylindrical core to form a cylindricalabrasive assembly having an outside diameter substantially the same asthe distance between said shafts.

4. The apparatus of claim 2 in which said units are I solid abrasivewheels.

5. The apparatus of claim 2 in which said units are brushes made ofbristles comprising abrasive material.

6. An apparatus for taper-grinding and flagging of filaments forsubsequent use as brush bristles, which comprises two rotatably mountedshafts, means for rotating said shafts at high speeds in directionsopposite to each other, a multiplicity of thin abrasive wheels regularlyspaced along each of said shafts, the wheels of one shaft beingstaggered with respect to the wheels of the other shaft and beingpositioned such that the wheels of one shaft extend into the spacesbetween, and not in contact with, adjacent wheels of the other shaft, acontinuous conveyor adapted to move a thin bed of filaments along a pathwhich is parallel to, and lies in a plane passing midway between, saidshafts, means for tightly clamping the central portion of said filamentsagainst movement with respect to said conveyor, while leaving the tipsof said filaments free to be bent, said conveyor being positionedsutficiently close to the periphery of said wheels so that the tips ofthe filaments being held by said conveyor are in contact with saidabrasive wheels.

7. An apparatus for taper-grinding and flagging brush bristles assembledin the form of a continuous belt comprising a thin bed of bristlesplaced in side-by-side alignment and sewn to a narrow continuous tapepositioned along the longitudinal axis of said beltgsaid apparatuscomprising two opposed, continuous conveyors adapted to press againstopposite sides of the central portion of said belt of bristles and totransport said belt in a longitudinal direction; means for driving saidconveyors in the same direction and at the same speed; two rotatablymounted shafts driven so as to rotate in opposite directions withrespect to each other; a multiplicity of thin abrasive disc-like wheelsaifixed to, and regularly spaced along, each of said shafts, the spacingbetween adjacent wheels being approximately twice the thickness of oneof said wheels; the peripheries of the wheels of one shaft extendinginto the spaces between adjacent wheels on the other shaft; said beltand the conveyors transporting said belt being positioned midwaybetween, and parallel to, said shafts and in close proximity to theperipheries of said abrasive wheels whereby the tips of said bristlesbrush into contact with each of said wheels while being transported bysaid conveyors; said wheels being driven at a high speed in a directiontoward said bristles.

8. An apparatus for taper-grinding and flagging syn thetic polymerfilaments assembled in the form of a continuous belt comprising a thinbed of filaments placed in side-by-side alignment and sewn to a narrowcontinuous tape positioned along the longitudinal axis of said belt;said apparatus comprising two opposed, continuous conveyors adapted topress against opposite sides of the central portion of said belt offilaments and to transport said belt in a longitudinal direction; meansfor driving said conveyors in the'same direction and at the same speed;two rotatably mounted shafts driven so as to rotate in oppositedirections with respect to each other; a cylindrical brush fixedlymounted on each of said shafts and being made of abrasive bristles, thediameter of each of said brushes being substantially the same as thedistance between said shafts; said belt and the conveyors transportingsaid belt being positioned midway between, and parallel to, said shaftsand sufficiently close to the perpiheries of said cylindrical brushesthat the tips of said filaments are contacted by said abrasive bristles;said cylindrical brushes being driven at high speed in a directiontoward said filaments.

9. The apparatus of claim 8 in which said abrasive bristles are lengthsof metallic wire coated with abrasive particles, and in which thosebristles are arranged in a regular pattern of rows such that, in anycross section perpendicular to the axis of the said brush, the bristlesare equally spaced around the brush at an angle between adjacentbristles of 2-45, measured at the center of the brush.

References Cited in the file of this patent UNITED STATES PATENTS1,078,507 Loomis Nov. 11, 1913 1,495,747 Izawa May 27, 1924 1,627,704Izawa May 10, 1927 1,888,675 Izawa Nov. 22, 1932 2,017,487 Elliot Oct.15, 1935 2,227,126 Cooke Dec. 31, 1940 2,365,396 Cunningham Dec. l9,1944 2,854,797 Van Clief Oct. 7, 1958

